Hello, I got the same problem. When I open XBMC ( OSX x86-64 & nightly ) it crashes on opening.
I think it has something to do with the Add-on I added like 4 months ago, after that I stopped using XBMC and removed it from my Macbook Pro.
I've been searching the internet for the solution. But so far, I have not yet find it.
Does somebody have the same problem as me? And if so, can someone tell me how to solve this problem?
Thanks!

Hi All very to day to this. I installed XBMC on my macbook this morning all was looking good then my macbook said i had a update so I proceded with the update to OSX 10.9.1 and since then it will not load xvmc says its from a unknown sour or provider have i got to update something else i have up dated the the mirror site to 12.3 but still the same I hope someone can help me. many thanks in advance

I've done everything still can't get it to open every time it asks if i want to reopen it i can hit ok or reopen and still gives me the same error message Application Specific Information:
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Error (1007) creating CGSWindow on line 263'

Ok heres what to do first go to this site and download apptrapp i run it on all my Macs http://onnati.net/apptrap/
Next delete XBMC drag it over to trash app trap will ask to delete all click ok.
Now go here http://xbmc.org/download/ make sure to download OSX version "Not the OSX x86-64"